Use as Listenable ?

[tzvc]

Hi there,

I'm experimenting with using StateNotifier through a StateNotifierProvider to drive a synced animation in my app. As the doc say StateNotifier is a "fork" of ValueNotifier, I was hoping I could use it directly in place of a Listenable in a AnimatedBuilder like so:

riverpod.Consumer(builder: (BuildContext context, riverpod.ScopedReader watch, Widget child) {
    final navH = watch(vavBarHorizontalValueProvider); // a StateNotifierProvider
    return AnimatedBuilder(
        animation: navH,
        builder: (context, _) {
            return Container(height: navH.value, width:navH.value); 
    });
})

ChangeNotifier extends Listenable so I could change it to a ChangeNotifierProvider but that's more boilerplate code. Is there any way to fix this? And is this solution viable at all?

[rrousselGit]

This is not possible. Why do you need that?

Le jeu. 19 nov. 2020 à 13:44, Théo champion notifications@github.com a écrit :

Hi there,

I'm experimenting with using StateNotifier through a StateNotifierProvider to drive a synced animation in my app. As the doc say StateNotifier is a "fork" of ValueNotifier, I was hoping I could use it directly in place of a Listenable in a AnimatedBuilder like so:

riverpod.Consumer(builder: (BuildContext context, riverpod.ScopedReader watch, Widget child) { final navH = watch(vavBarHorizontalValueProvider); // a StateNotifierProvider return AnimatedBuilder( animation: navigationBloc.verticalBottomNavBarValue, builder: (context, ) { return Container(height: navH.value, width:navH.value); }); })

ChangeNotifier extends Listenable so I could change it to a ChangeNotifierProvider but that's more boilerplate code. Is there any way to fix this? And is this solution viable at all?

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[tzvc]

@rrousselGit so I can use it to drive an animation like so:

riverpod.Consumer(builder: (BuildContext context, riverpod.ScopedReader watch, Widget child) {
    final navH = watch(vavBarHorizontalValueProvider); // a StateNotifierProvider
    return AnimatedBuilder(
        animation: navH, // this doesnt work, StateNotifier doesnt extend the required Listenable
        builder: (context, _) {
            return Container(height: navH.value, width:navH.value); 
    });
})

The code above works if I replace the StateNotifierProvider by a ChangeNotifierProvider but its just a little bit more boilerplate code :)

[rrousselGit]

If you are using Riverpod, you do not need an AnimatedBuilder to rebuild your widget when the state changes. watch(myProvider.state) takes care of that

StateNotifier cannot implement Listenable. It is not possible

[lucavenir]

Hi @rrousselGit , I do realize this is an old conversation, but...

StateNotifier cannot implement Listenable. It is not possible

... why? I can't answer this question myself. This is just pure curiosity.